DQL:数据查询语言(凡是带有select关键字的都是查询语句) DML:数据库操作语言(凡是对表当中的数据进行增删改的都是DML){insert delete update}操作数据的 DDL:数据库定义语言(凡是带有create,drop,alter的是DDL) 操作表的结构进行操作 DCL:数据控制语言(授权grant和安全级别deny) TCL:数据库事务语言(commit提交 roll...
DDL: data definition language, such as CREATE, ALTER, DROP DQL: data query language, such as SELECT DML: data manipulation language, such as INSERT, UPDATE, DELETE DCL: data control language, such as GRANT, REVOKE TCL: transaction control language, such as COMMIT, ROLLBACK For a backend en...
3. A user runs a DDL command such as CREATE, DROP, RENAME, or ALTER. 4. The database issues an implicit COMMIT statement before and after every DDL statement. If the current transaction contains DML statements, then Oracle Database first commits the transaction and then runs and commits the...
DDL: data definition language, such as CREATE, ALTER, DROP DQL: data query language, such as SELECT DML: data manipulation language, such as INSERT, UPDATE, DELETE DCL: data control language, such as GRANT, REVOKE TCL: transaction control language, such as COMMIT, ROLLBACK For a backend en...
DDL: data definition language, such as CREATE, ALTER, DROP DQL: data query language, such as SELECT DML: data manipulation language, such as INSERT, UPDATE, DELETE DCL: data control language, such as GRANT, REVOKE TCL: transaction control language, such as COMMIT, ROLLBACK For a backend en...